FluMist Quadrivalent, a vaccine to prevent seasonal influenza in people ages 2 years through 49 years, has been approved today by the U.S. Food and Drug Administration. FluMist Quadrivalent is the first influenza vaccine to contain four strains of the influenza virus, two influenza A strains and two influenza B strains.

Like the already approved FluMist (trivalent), the quadrivalent vaccine contains weakened forms of the virus strains and is administered as a spray into the nose.

There are two types of influenza viruses that cause illness and death in people: influenza A and B. Each year, the FDA-approved seasonal influenza vaccine includes three strains of influenza virus, two strains of influenza A and one of influenza B. During a typical influenza season, there may be two different influenza B strains circulating, or the B strain selected for inclusion in the trivalent influenza vaccine may not be the influenza B strain that eventually circulates causing illness. The inclusion of a second B strain in FluMist Quadrivalent increases the likelihood of adequate protection against circulating influenza B strains.

“Illness caused by Influenza B virus affects children, particularly young and school-aged, more than any other population,” said Karen Midthun, M.D., director of the FDA’s Center for Biologics Evaluation and Research. “A vaccine containing the four virus strains most likely to spread and cause illness during the influenza season offers an additional option to aid in influenza prevention efforts.”

Vaccination is the best method to prevent influenza. Influenza seasons are unpredictable and can be severe, even deadly. Between 1976 and 2007, estimates of seasonal influenza-associated deaths in the United States ranged from a low of about 3,000 to a high of about 49,000 people.

The safety and effectiveness of FluMist Quadrivalent is supported by studies conducted previously for the FluMist trivalent formulation and three new clinical studies conducted in the United States involving about 4,000 children and adults. The studies demonstrated that the immune responses were similar between FluMist Quadrivalent and FluMist.

Adverse reactions reported were similar among those receiving FluMist Quadrivalent and FluMist. The most commonly reported adverse reactions were runny or stuffy nose in both children and adults, and headache and sore throat in adults.

FluMist Quadrivalent is manufactured by MedImmune LLC of Gaithersburg, Md.

The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.